In this article, we investigate the making of research infrastructures. Our aim is to identify the relevant context factors, actor constellations, organizational settings, and strategies for a mere service to become an actual infrastructure. To this end, we conducted 36 case studies of non-commercial and commercial research services. Our research sheds light on the motivations and logics behind infrastructure development and the reasons why not every service succeeds in becoming one. We believe that the results of this study are therefore of practical relevance, especially for persons and organizations that want to create and sustain research infrastructured.